M
TFT-LCD DC-DC Converters with
Operational Amplifiers
______________________________________________________________________________________
11
Pin Description (continued)
NAME
MAX1517
PIN
MAX1516
MAX1518
FUNCTION
20
N.C.
N.C.
OUT5
Operational-Amplifier 5 Output. Not Internally Connected for the MAX1517 and
MAX1516.
21
LX
LX
LX
N-Channel Power MOSFET Drain and Switching Node. Connect the inductor and
Schottky diode to LX and minimize the trace area for lowest EMI.
22
IN
IN
IN
Supply Voltage Input. IN can range from 2.6V to 5.5V.
23
FB
FB
FB
Step-Up Regulator Feedback Input. Regulates to 1.236V (nominal). Connect a resistive
voltage-divider from the output (V
MAIN
) to FB to analog ground (AGND). Place the
divider within 5mm of FB.
24
COMP
COMP
Step-Up Regulator Error-Amplifier Compensation Point. Connect a series RC from
COMP to AGND. See the
Loop Compensation
section for component selection
guidelines.
25
FBP
FBP
FBP
Gate-On Linear-Regulator Feedback Input. FBP regulates to 1.25V (nominal). Connect
FBP to the center of a resistive voltage-divider between the regulator output and AGND
to set the gate-on linear-regulator output voltage. Place the resistive voltage-divider
close to the pin.
26
DRVP
DRVP
DRVP
Gate-On Linear-Regulator Base Drive. Open drain of an internal n-channel MOSFET.
Connect DRVP to the base of an external pnp pass transistor. See the
Pass-Transistor
Selection
section.
27
FBN
FBN
FBN
Gate-Off Linear-Regulator Feedback Input. FBN regulates to 250mV (nominal).
Connect FBN to the center of a resistive voltage-divider between the regulator output
and REF to set the gate-off linear-regulator output voltage. Place the resistive voltage-
divider close to the pin.
28
DRVN
DRVN
DRVN
Gate-Off Linear-Regulator Base Drive. Open drain of an internal p-channel MOSFET.
Connect DRVN to the base of an external npn pass transistor. See the
Pass-Transistor
Selection
section.
29
DEL
DEL
DEL
High-Voltage Switch Delay Input. Connect a capacitor from DEL to AGND to set the
high-voltage switch startup delay.
30
CTL
CTL
CTL
High-Voltage Switch Control Input. When CTL is high, the high-voltage switch between
COM and SRC is on and the high-voltage switch between COM and DRN is off. When
CTL is low, the high-voltage switch between COM and SRC is off and the high-voltage
switch between COM and DRN is on. CTL is inhibited by the undervoltage lockout and
when the voltage on DEL is less than 1.25V.
31
DRN
DRN
DRN
Switch Input. Drain of the internal high-voltage back-to-back p-channel MOSFETs
connected to COM.
32
COM
COM
COM
Internal High-Voltage MOSFET Switch Common Terminal. Do not allow the voltage on
COM to exceed V
SRC
.